Fluorescent electric lights are used for illuminating a variety of environments where combustible materials may be present because fluorescent lamps typically produce less heat during operation than incandescent lamps. Portable electric lights are utilized in other hazardous environments as well, often in the presence of wet or corrosive materials. To combat the stresses induced by these environments and to avoid hazards caused by breakage, existing portable work lights typically include metal guards for protecting the electric lamps inside. One example of such a light, the Model XP65 Fluorescent Portable Inspection Light of the Stewart R. Browne Manufacturing Company, includes a guard having intersecting flat metal bars forming a protective grid about an elongated fluorescent tube. Other work lights comprise a protective glass globe surrounding the electric lamp.
Utilizing metal or similar electrically-conductive guards does not preclude the possibility of electrical arcs or shocks in charged or wet environments, however. Metal guards additionally may spark should the lights be dropped onto or otherwise impact certain substances, potentially igniting flammable materials or combustible atmospheric gasses. Although less likely to conduct electricity, many glass protective surfaces may break if dropped or impacted with sufficient force, exposing the interior lamps to the hazardous environments and vice-versa. Other glass-globed structures fail to insulate the electric lamps from their environments, permitting atmospheric gasses to contact the lamps with potentially dangerous results. Recognizing these and other perils present in artificially illuminating hazardous environments with electric lamps Underwriters Laboratories, Inc. ("UL") has promulgated Standard 781 for "Portable Electric Lighting Units for Use in Hazardous (Classified) Locations" (which standard is incorporated herein in its entirety by this reference). Until recently, however, only metallic guards were considered sufficiently protective and durable to meet the UL Standard.